Snes9x 1.55 released!

Thanks to some dedicated work by qwertymodo, Snes9x 1.55 now has MSU-1 support, including the MSU-1 distribution pack. The MSU-1 is an SNES expansion chip invented by byuu (author of higan), you can find some more information about it here. LuigiBlood also did some work on increasing the BS-X Satellaview support.
Tmkk kindly provided a macOS build, so mac users should finally be able to upgrade.
Other than that there are some game fixes and housekeeping work.